516 SPHAEROCOCCACEAE. 



shallow water on St. David's Island, in the bays of St. George's, and on the 

 South Shore. (Phye. Bor.-Am. 1931 — as GracUaria dichotomo-flaiellata 

 Crouan.) 



Gracilaria horizontalis Collins & Hervey, is a thick, tough, fleshy, cartilag- 

 inous plant, expanding horizontally from a central irregular disc, with short 

 thick crowded scarcely attenuate branches, and closely adherent to the sub- 

 stratum or its overgrown parts by coarse haptera. The plant seems, from the 

 authors' description, to be closely related to Gracilaria crassissima Crouan 

 (J. Ag. Sp. Alg. 3*: 78. 1901 — type from Guadeloupe), if not identical with it. 



Hypnea musciformis (Wulf.) Lamour. is a copiously and somewhat vir- 

 gately branched dusky red plant with terete main axes about J of a line in 

 diameter. Its longer filiform branches are often hooked or incurved at the 

 apex and act somewhat like tendrils in grasping other algae or other branches 

 of its ow-n kind. Its shorter branchlets are taper-pointed and sometimes a 

 little spine-like. It occasionally resembles the narrower more terete conditions 

 of Gracilaria ferox, but the tetrasporangia, as in other species of Hypnea, are 

 confined to som.ewhat swollen spear-like branchlets instead of being scattered 

 through the cortex in general, and under a compound microscope the tetraspores 

 are seen to be arranged in rows of four (zonate) instead of in collateral pairs 

 (cruciate). (Phyc. Bor.-Am. 2185.) 



Hypnea spinella (Ag.) Kiitz. forms low densely intertangled dark red or 

 scarlet mats or cushions on rocks in shallow water in Hamilton Harbor. Its 

 main axes are terete, angular, or slightly flattened, about i of a line in diam- 

 eter, and it has numerous short sharp-pointed branches that become rigid and 

 spiny on drying, giving the plant somewhat of the aspect of a miniature 

 Kncheuma. The tetrasporangia are borne on spool-shaped or conic, usually 

 rostrate, enlargements of short branchlets. 



Family RHODYMENIACEAE. 



Cordylecladia irregularis Harv. is a rather rigid irregularly branched 

 thread-like plant (about 1— 3 of a line in diameter) that forms dense mats or 

 creeps among other algae near the low-water mark. When living its color is 

 a greenish or brownish red with touches of a steel-blue iridescence. Its 

 branching is usually very irregular but often shows a tendency to a secund 

 arrangement; occasionally opposite branches are found. The tetrasporangia 

 occur on pod-like enlargements of the ends of certain branchlets. The species 

 sometimes bears a slight resemblance to Wiirdemannia setacea, but it is 

 coarser, the branches are less acute and apparently do not anastomose; and 

 the filaments are hollow, as may be determined by examination of cross-sections 

 with a hand-lens. It scarcely adheres to paper on drying. [Phyc. Bor.-Am. 

 2186, as C. rigens (Ag.) Collins & Hervey.*] 



Chrysymenia • uvaria (L.) J. Ag. may be recognized by its suggestiveness 

 of elongate, branched, usually lax clusters of red or brownish-red grapes. In 



* The type of Sphaerococctis rigens Ag. is a .Japanese plant different in struc- 

 ture from the Bermudian and West Indian. 



